Data as of .
CPST vs SEPU: which one stands where?
As of Sep 21, 2026 SEPU can fall 1.4% before its buffer engages and CPST 0.2%, and CPST resets 1 days sooner.
These are two different products. CPST is a floor fund, which caps how far a holder can fall. SEPU is a buffer fund, which absorbs the first part of a fall and leaves everything below it with the holder.
Where each one stands today
CPST resets first, on Aug 31, 2027, 344 days from now; SEPU runs to Aug 31, 2027, 345 days. A fall from here reaches CPST’s buffer after 0.2% and SEPU’s after 1.4%. Both track SPY, so what separates them is where each is in its own period.
Every figure is ETFIQ’s own, from the issuer’s published outcome-period terms. A buffer ETF holds FLEX options on its reference index rather than shares, so there is no holdings overlap between two of them to report.
Performance, window by window
| Window | Total return | Gap to the reference | ||
|---|---|---|---|---|
| CPST | SEPU | CPST | SEPU | |
| 3 months | +1.1% | +1.5% | −1.2 pts | −0.8 pts |
| 6 months | +4.1% | +12.9% | −14.0 pts | −5.1 pts |
| 1 year | +5.0% | +11.6% | −11.6 pts | −5.0 pts |
| CPST Calamos S&P 500 ® Structured Alt Protection ETF - September Absorbs the whole loss on SPY and caps the gain at 8.0%, over a period ending Aug 31, 2027 | SEPU AllianzIM U.S. Equity Buffer15 Uncapped ETF - Sep Absorbs the first 15% of loss on SPY and does not cap the gain, over a period ending Aug 31, 2027 | |
|---|---|---|
| Issuer | Calamos | AllianzIM |
| Reference index | SPY | SPY |
| Buffer | 100% | 15% |
| Outcome period | Sep 1, 2026 to Aug 31, 2027 | Sep 1, 2026 to Aug 31, 2027 |
| Days left | 344 | 345 |
| Starting cap | +8.0% | uncapped |
| Can still gain | not published | uncapped |
| Fall before buffer | 0.2% | 1.4% |
| Protection left, index points | 100.0% of 100.0% | 15.0% of 15.0% |
| Index return this period | 0.0% | +0.9% |
| Fund return this period | +0.1% | +0.7% |
| State today | Buffer working | Uncapped |
| Expense ratio | 0.69% | 0.74% |
| Net assets | $37m | $162m |
CPST in plain words
The fund's price can fall 0.2% from here before the buffer starts absorbing losses, by the issuer's figure. In index terms, SPY can fall 0.0% from today's level to the point where the buffer begins. Protection left, in index points: 100.0% of the 100.0% buffer still sits below today's SPY level. 344 days remained on Sep 21, 2026. On Aug 31, 2027 the period ends and a new cap is set.
SEPU in plain words
This fund has no cap. It takes a share of any further rise in SPY. The fund's price can fall 1.4% from here before the buffer starts absorbing losses, by the issuer's figure. In index terms, SPY can fall 0.9% from today's level to the point where the buffer begins. Protection left, in index points: 15.0% of the 15.0% buffer still sits below today's SPY level. 345 days remained on Sep 21, 2026.
Questions people ask
- Which resets first, CPST or SEPU?
- CPST ends its outcome period on Aug 31, 2027 and SEPU on Aug 31, 2027. A new cap is set the day after each.
- Which is cheaper, CPST or SEPU?
- CPST charges 0.69% a year and SEPU charges 0.74%, so CPST is cheaper. Fees come from each fund's prospectus.
Other comparisons
Where these figures came from
ETFIQ links to the documents behind every figure. It is not affiliated with any issuer, and a link is not an endorsement.
Cite this page. ETFIQ, CPST against SEPU, data as of Sep 21, 2026. https://etfiq.com/compare/buffer/cpst-vs-sepu Free to use with attribution; the underlying files are at Open data.